Sewing round shapes presents a few special problems I'll try to
address in this instruction segment. The main thing to contend with in
any curved sewing is the fact that outer part of a seam needs to become
longer than the inner (stitched) part. As you can see below in the photos
where the welt has been sewn to the end pieces, the welt fabric has flared
open where I've snipped it to become longer on the outer edge.If you don't have bolster foam you can buy it on our Supplier's
Page. In a pinch (I've done it) you can make the filling by cutting,
say, a 4" rectangle piece of foam, trimming off the sharp edges with shears,
and wrapping it in bonded polyester (Dacron) until the right size. If you
use several layers of Dacron it should finish 1 1/2' or more bigger than
the cover so it doesn't squish the first time it's used.

I decided not to put a Dacron (poly) wrap on the foam filling but
I still wanted a nice tight fit so I made my finished measurements a 1/2"
smaller than the filling. You can find the distance around a circle by
multiplying the diameter x pi(3.14). Add for your seam allowance or zipper.
I used my foam for a pattern for the round end pieces but you could use
a compass. Cutting to the outside of my chalk line gave me the finished
measurement I wanted.

Notch the top and bottom of the end piece and use it for a pattern
for the other end. Mark the top on both pieces.

Sew fabric to one side of zipper as per previous instructions. Then
turn and sew the other side to the zipper. If sewing the zipper this way
is too bulky, too awkward or just makes you crazy then, try making a separate
zipper boxing. Just don't make it so wide it can be seen when finished.
Or sew in a 1-2" seam on each end (backstitch) and handsew it closed when
you are done filling the cushion.Fold and notch what will be the top of this cushion.

Sew the welt cord to the end piece just as you would for a square
pillow except snip the fabric every inch or so to release the fabric to
make the turn. Off-set your starting point so that you don't finish right
at the same spot where the zipper will be and cause a bump from too many
layers of fabric..

End piece with welt cord sewn to it.

Line up the top notch of the end piece on top of the top notch of
the main cushion piece. Get the sewing machine needle between the cording
and the stitching. As you sew check a few times to make sure the bottom
notch of the end piece is going to lineup with the center of the zipper.
You can either go ahead and sew all the way around or flip the whole cushion
over and start again from the top notch and sew the plate fabric to the
the end piece. Turn right side out and make sure no stitching shows.

Finished cover.

Other round sewing:

It would seem a simple task making a round cushion for a round dining
room chair seat but this can be one of the most difficult projects to get
to look right. One problem is with the filling the other with the sewing.
Factory made foam fill is often molded and shaped to fit. If the foam is
in good condition sometimes it can be steamed a little to expand it back
to it's original fullness. Or if it needs a wrap sew 2 half layers
together of bonded Dacron and turn the seams to the inside then put the
foam in. You can also do this with a new piece of 1" foam. And/or you can
make a ticking out of a lightweight fabric and put the fill in there first
then into new cover. You can glue instead of sew if you make a ticking
as it will help hide the Dacron's edge from showing through the new cover.Top stitchingand installing a welt can both add "body" to a round cushion helping it
to retain it's shape. The ends to the above bolster could also have been
top stitched instead of welted. On round or shaped cushions (like ones
that go around rungs on dining chairs) sometimes it's simply easier to
do them with a boxing if you want a nice tailored look.